Computational modelling of the cerebral cortical microvasculature: effect of x-ray microbeams versus broad beam irradiation

Microbeam Radiation Therapy is an innovative pre-clinical strategy which uses arrays of parallel, tens of micrometres wide kilo-voltage photon beams to treat tumours. These x-ray beams are typically generated on a synchrotron source. It was shown that these beam geometries allow exceptional normal tissue sparing from radiation damage while still being effective in tumour ablation. A final biological explanation for this enhanced therapeutic ratio has still not been found, some experimental data support an important role of the vasculature. In this work, the effect of microbeams on a normal microvascular network of the cerebral cortex was assessed in computer simulations and compared to the effect of homogeneous, seamless exposures at equal energy absorption. The anatomy of a cerebral microvascular network and the inflicted radiation damage were simulated to closely mimic experimental data using a novel probabilistic model of radiation damage to blood vessels. It was found that the spatial dose fractionation by microbeam arrays significantly decreased the vascular damage. The higher the peak-to-valley dose ratio, the more pronounced the sparing effect. Simulations of the radiation damage as a function of morphological parameters of the vascular network demonstrated that the distribution of blood vessel radii is a key parameter determining both the overall radiation damage of the vasculature and the dose-dependent differential effect of microbeam irradiation.

New irradiation geometry for microbeam radiation therapy

Microbeam radiation therapy (MRT) has the potential to treat infantile brain tumours when other kinds of radiotherapy would be excessively toxic to the developing normal brain. MRT uses extraordinarily high doses of x-rays but provides unusual resistance to radioneurotoxicity, presumably from the migration of endothelial cells from 'valleys' into 'peaks', i.e., into directly irradiated microslices of tissues. We present a novel irradiation geometry which results in a tolerable valley dose for the normal tissue and a decreased peak-to-valley dose ratio (PVDR) in the tumour area by applying an innovative cross-firing technique. We propose an MRT technique to orthogonally crossfire two arrays of parallel, nonintersecting, mutually interspersed microbeams that produces tumouricidal doses with small PVDRs where the arrays meet and tolerable radiation doses to normal tissues between the microbeams proximal and distal to the tumour in the paths of the arrays.

MMP-19: cellular localization of a novel metalloproteinase within normal breast tissue and mammary gland tumours

Matrix metalloproteinases (MMPs) are instrumental in promoting and facilitating the spread of malignant diseases and in the de novo formation of blood vessels. This study has mapped the immunoreactivity of a novel, angiogenesis-related metalloproteinase--MMP-19--in normal breast tissue and in benign and malignant breast lesions and compared this pattern of expression with that of MMP-2. In the normal resting mammary gland, MMP-19 was strongly expressed in the myoepithelial layer of the ductal system; the alveolar and ductal epithelia displayed considerable, but lobule-specific, variations in labelling intensity. MMP-19 was also present within the smooth muscle and endothelial layers of large and medium-sized blood vessels, as well as within capillary walls. In benign lesions, all tumour cells and their surrounding vasculature were uniformly and strongly immunoreactive for MMP-19. Progression towards an invasive phenotype and neoplastic dedifferentiation led to the disappearance of MMP-19 from tumour cells and blood vessels and a concomitant rise in the levels of MMP-2. In vitro experiments conducted with isolated smooth muscle cells cultivated on a solid substratum, or within the interstices of a collagen matrix, indicated that the expression of MMP-19 is influenced by the architecture of the surrounding extracellular matrix.

Human papillomavirus positive squamous cell carcinoma of the oropharynx: a radiosensitive subgroup of head and neck carcinoma

BACKGROUND

Epidemiologic evidence points to a connection between viral infection by the human papillomavirus (HPV) and a subgroup of squamous cell carcinoma of the oropharynx. To assess the impact of HPV infection on the response of these tumors toward radiotherapy, the authors retrospectively determined the presence of the virus and the integrity of the viral E2 gene in tumors of patients who have undergone curative irradiation.

METHODS

Paraffin embedded biopsies from 99 patients were analyzed for HPV infection and E2 gene integrity by multiplex PCR. The experimental findings were correlated with clinical characteristics, known risk factors, and treatment outcome.

RESULTS

Fourteen of 99 tumors were HPV positive (11 HPV16, 1 HPV33, 1 HPV35, and 1 HPV45). Human papillomavirus positivity was closely linked to female gender (odds ratio [OR], 5.75; P = 0.004), age older than 56 years (OR, 7.42; P = 0.012), nonsmokers (OR, 21.33; P = 0.00001), and alcohol abstainers (OR, 5.35; P = 0.012). There was an inverse association with p53 nuclear immunoreactivity (OR, 0.06; P = 0.008). The Kaplan-Meier survival estimates showed a better local control (P = 0.050, log-rank) and a better overall survival (P = 0.046, log-rank) for patients with HPV positive tumors. In the multivariate analysis, HPV positivity remained to be associated with a lower risk of local failure (risk ratio [RR], 0.31; P = 0.048). Four of 11 HPV16 positive tumors had a disrupted E2 gene. Only tumors with a disrupted E2 gene manifested local treatment failure.

CONCLUSIONS

Human papillomavirus positivity designates a specific subgroup of oropharyngeal squamous cell carcinomas of the oropharynx that arise preferentially among individuals with no consumption of tobacco and alcohol and that have a favorable outcome attributable to an increased sensitivity toward radiotherapy.

Expression of hypoxia-inducible factor-1alpha: a novel predictive and prognostic parameter in the radiotherapy of oropharyngeal cancer

Hypoxia has long been recognized as detrimental to the successful treatment of malignant tumors with ionizing radiation. Because hypoxia-inducible factor (HIF)-1alpha plays an essential role in oxygen homeostasis in vitro, we explored the predictive potential of this factor in a cohort of 98 patients with squamous cell cancer of the oropharynx, who were treated by curative radiation therapy. Ninety-four % of the primary tumors showed overexpression of HIF-1alpha, relative to the surrounding tissue, as determined by immunohistochemistry. The degree of HIF-1alpha immunoreactivity correlated inversely with both the rate of complete remission of the primary tumor (odds ratio, 0.33; P = 0.03) and lymph node metastases (odds ratio, 0.34; P = 0.02) as well as with local failure-free survival (risk ratio, 2.15; P = 0.006), disease-free survival (risk ratio, 2.01; P = 0.008), and overall survival (risk ratio, 2.17; P = 0.002). The multivariate analysis revealed the predictive power of HIF-1alpha to be independent of other covariables. We conclude that HIF-1alpha is overexpressed in the vast majority of patients with squamous cell cancer of the oropharynx and that the degree of expression has predictive and prognostic significance in individuals undergoing curative radiation therapy.

Involvement of the hepatocyte growth factor/scatter factor receptor c-met and of Bcl-xL in the resistance of oropharyngeal cancer to ionizing radiation

The activation of cytoplasmic signal transduction pathways by a number of growth factors and their tyrosine-kinase receptors, including hepatocyte growth factor/scatter factor (HGF/SF) and its receptor c-met, exerts an inhibitory influence on apoptosis induced by ionizing radiation in vitro. The clinical relevance of the aforementioned ligand-receptor pair, of Bcl-xL, which is targeted by HGF/SF/c-met signaling, and of Bcl-2, was assessed by evaluating their predictive and prognostic impact in a cohort of 97 patients with radically irradiated squamous cell cancers of the oropharynx. Immunohistochemical expression of c-met and Bcl-xL was correlated with decreased rates of complete remission of the primary tumor in both the univariate (c-met: P = 0.01; Bcl-xL: P = 0.001) and multivariate analyses. Expression of c-met was, moreover, a significant and independent predictor of impaired local failure-free survival (P = 0.003), disease-free survival (P = 0.003) and overall survival (p = 0.001). Bcl-2 expression was, on the other hand, associated with a favorable outcome, in terms of both local failure-free survival (P = 0.01) and overall survival (P = 0.001). In accordance with in vitro data, c-met and Bcl-xL appear to be involved in the resistance of oropharyngeal cancers to ionizing radiation, and may therefore represent attractive targets for radiosensitization.

Intratumoral microvessel density predicts local treatment failure of radically irradiated squamous cell cancer of the oropharynx

PURPOSE

To determine the predictive value of intratumoral microvessel density (IMD), and of the expression of p53, vascular endothelial growth factor (VEGF) and thrombospondin-1 (TSP-1) for the radiocurability of patients with squamous cell cancer of the oropharynx.

MATERIALS AND METHODS

139 patients with squamous cell cancer of the oropharynx were radically irradiated (median dose, 74 Gy) between 1991 and 1997. Biopsies from 100 patients were processed for immunohistochemistry. IMD was determined in hot spot areas of tissue stained with anti-CD31 at a magnification of x200. Staining for p53 was considered positive if more than 10% of the cell nuclei overexpressed the protein. Immunostaining of VEGF and TSP-1 was assessed semiquantitatively.

RESULTS

Increasing IMD (range, 54-282) was strongly correlated with incomplete remission of both the primary tumors (p = 0.01) and lymph node metastases (p = 0.02). Moreover, multivariate Cox regression analysis revealed local failure-free survival to decline with increasing IMD (IMD continuous: risk ratio = 1.01 per increase of 1 microvessel, p = 0. 0001; IMD categorical: </= 80: baseline, 81-110: risk ratio = 2.71, 111-130: risk ratio = 4.55, > 130: risk ratio = 13.01). Neither the expression of p53, nor that of VEGF or TSP-1 was associated with the treatment outcome or IMD, but VEGF and TSP-1 expression were positively correlated (p = 0.02).

CONCLUSION

IMD represents a powerful and independent predictive factor for local treatment failure in radically irradiated patients with squamous cell cancer of the oropharynx.

Somatostatin receptor in breast cancer and axillary nodes: study with scintigraphy, histopathology and receptor autoradiography

We conducted a prospective analysis of somatostatin receptor scintigraphy using (111)In radiolabeled pentetreotide, a somatostatin analog, in patients with breast cancer in the aim to visualize the primary tumor and axillary or parasternal metastatic extension because some malignant breast tumors express somatostatin receptors (SS-R) in 50%, approximately. An analysis of SS-R was performed by autoradiography.

PATIENTS AND METHODS

Thirteen patients with clinically suspected breast tumors (T1, T2), and at least one palpable axillary node (N1) were included. In vivo planar scintigrams were acquired 1, 4, and 24 h after subcutaneous, then after intravenous injections (24 h delay between injections). Improved (111)In-pentetreotide uptake in invaded nodes after subcutaneous injection was hypothesized. Ex vivo scintigrams of surgical specimens were also acquired immediately after tumor resection and axillary dissection. Pathological examination and receptor autoradiography were performed on all surgical specimens.

RESULTS

Among 11 pathologically proven malignant tumors (9 ductal and 2 lobular carcinomas), only four were scintigraphically visible although six expressed SS-R receptors in vitro. Among six pathologically proven malignant nodes, four expressed SS-R, including two visualized scintigraphically. Scintigrams acquired after subcutaneous injections were less sensitive than after intravenous injections. There were no false positive. False negatives occurred in cases with small tumors with low-density or heterogeneously distributed SS-R. There was no significant difference by histological type or prognostic factors.

CONCLUSION

Somatostatin receptor scintigraphy does not appear to be sensitive enough to evaluate axillary node extension of breast cancer or even to confirm the presence of tumoral tissue, and this whatever the administration route for (111)In-pentetreotide.

Immunohistochemical localization of somatostatin receptor sst2A in human pancreatic islets

Somatostatin and octreotide inhibit endocrine pancreatic functions in man, via specific somatostatin receptors. However, the cellular distribution of the different somatostatin receptor subtype proteins has not been determined in the human pancreas. Here, the immunohistochemical distribution of the sst2A receptor was investigated using the sst2A receptor specific anti-peptide antibody R2-88 in cryostat as well as in formalin-fixed paraffin-embedded sections of human pancreatic tissue, and compared with insulin, glucagon and somatostatin immunostaining of adjacent sections. All pancreatic islets were immunostained with R2-88. Most islet cells were labeled: the sst2A receptors were present in insulin as well as glucagon producing cells, but were not detected in intra-islet vessels nor in adjacent acinar tissue. Absorption of the sst2A antibody with 100 nM of the antigen peptide abolished specific staining in tissue sections. Immunohistochemical staining with R2-88 correlated with the labeling observed after receptor autoradiography using the sst2-preferring radioligand, 125I-Tyr3-octreotide. Therefore, the clinical efficacy of octreotide on glucagon and insulin release can be explained by the presence of sst2A receptors in human A and B pancreatic islet cells. Moreover, absence of sst2A receptors in human acinar tissue suggests that the action of somatostatin on pancreatic exocrine secretion is mediated either indirectly or through a different somatostatin receptor subtype on acinar cells.

Immunohistochemical localization of somatostatin receptors sst2A in human tumors

Human tumors frequently express somatostatin receptors. However, none of the receptor subtype proteins have been individually visualized in normal or neoplastic human tissues. Here, the distribution of the sst2A receptor was investigated using immunohistochemistry with the specific anti-peptide antibody R2-88 in 47 human tumors. All tumors selected for their abundance of sst2 mRNA and/or strong binding of the sst2-preferring ligand 125I-labeled Tyr3-octreotide were specifically immunostained with R2-88. Conversely, all tumors without somatostatin binding or expressing predominantly other somatostatin receptor subtype mRNAs (sst1 or sst3) were not specifically immunostained by R2-88. Specificity was shown in immunoblots, demonstrating receptor migration as a 70-kd broad band. In immunohistochemical and immunoblotting experiments, the abolition of staining after antibody blockade with antigen peptide was demonstrated. Immunostaining was identified in cryostat and in formalin-fixed, paraffin-embedded sections. Heat-induced epitope retrieval was necessary to visualize sst2A receptors in formalin-fixed sections. Moreover, because of occasional high nonspecific staining, the demonstration of complete abolition of immunostaining by treatment with antigen peptide was a prerequisite for the correct identification of sst2A-positive tumors. The sst2A receptors were clearly located at the membrane of the tumor cells. These results provide the first localization of a somatostatin receptor subtype in human tissues at the cellular level. The sst2A receptor identification and visualization in tumors with simple immunohistochemical methods in formalin-fixed, paraffin-embedded material will open new diagnostic opportunities for pathologists.

Neurotensin receptors: a new marker for human ductal pancreatic adenocarcinoma

BACKGROUND/AIMS

New imaging possibilities for early diagnosis of the devastating exocrine pancreatic adenocarcinomas would be highly welcome. Recently, pancreatic neuroendocrine tumours have been successfully visualised in vivo on the basis of their high density of receptors for the regulatory peptide somatostatin. Unfortunately, exocrine pancreatic tumours do not express sufficient amounts of somatostatin receptors. Therefore over-expression of other regulatory peptide receptors in these tumours needs to be found.

METHODS

Receptors for the regulatory peptide neurotensin were evaluated in vitro by receptor autoradiography in 24 ductal pancreatic adenocarcinomas, 20 endocrine pancreatic cancers, 18 cases of chronic pancreatitis, and 10 normal pancreatic glands.

RESULTS

Some 75% of all ductal pancreatic adenocarcinomas, most of them differentiated, were neurotensin receptor positive, whereas endocrine pancreatic cancers did not express neurotensin receptors. No neurotensin receptors were found in chronic pancreatitis or normal pancreatic tissues, including pancreatic acini, ducts, and islets.

CONCLUSIONS

The selective and high expression of neurotensin receptors in ductal pancreatic adenocarcinomas could form the molecular basis for potential clinical applications, such as in vivo neurotensin receptor scintigraphy for early tumour diagnosis, radiotherapy with radiolabelled neurotensin analogues, and chemotherapy with neurotensin receptor antagonists.

Distribution of somatostatin receptors in normal and neoplastic human tissues: recent advances and potential relevance

This short review describes the localization of somatostatin receptors with in vitro receptor autoradiography techniques in several non-classical, normal human somatostatin target tissues as well as in selected human tumors. In addition to brain, gut and neuroendocrine localizations, somatostatin receptors are expressed in most lymphatic tissues, including gut-associated lymphatic tissue, spleen and thymus; in the cortical and medullary area of the kidney; in the stroma of the prostate and in the epithelial cells of the thyroid. Among human tumors, the extremely high density of somatostatin receptors in medulloblastomas should be stressed as well as the favorable prognostic role of the presence of somatostatin receptors in neuroblastomas. Moreover, several types of mesenchymal tumors have somatostatin receptors as well. The receptor subtypes expressed by distinct tumors may vary: Whereas medulloblastomas and neuroblastomas predominantly express sst2, prostate cancers express sst1 rather than sst2. A further emerging somatostatin target is represented by the peritumoral veins, also known to express sst2 receptors. The multiple somatostatin targets in normal and pathological human tissues represents the basis for potential diagnostic and clinical applications of somatostatin analogs.

Visualization of the thymus by substance P receptor scintigraphy in man

Substance P, an 11-amino acid neuropeptide, has an important role in modulating pain transmission through neurokinin 1 and 2 receptors. Substance P and other tachykinins may also play a role in the pathogenesis of inflammatory diseases. In this study we present the results concerning the metabolism of the substance P analogue [111In-DTPA-Arg1]-substance P in man, as well as the visualization of the thymus in patients with immune-mediated diseases. Twelve selected patients were investigated, comprising five with inflammatory bowel disease, one with ophthalmic Graves' disease, one with sclerosing cholangitis, one with Sjögren's syndrome, one with rheumatoid arthritis, one with systemic lupus erythematosus and two with myasthenia gravis. During and after intravenous administration of 150-250 MBq (2.5-5.0 microg) [111In-DTPA-Arg1]-substance P, blood pressure, heart rate and oxygen saturation were monitored. Radioactivity was measured in blood, urine and faeces during the 48 h after injection. Planar and single-photon emission tomographic images were obtained 4 and 24 h after injection. After administration of [111In-DTPA-Arg1]-substance P, a transient flush was observed in all patients. Degradation of [111In-DTPA-Arg1]-substance P started in the first minutes after administration, resulting in a half-life of 10 min for the total plasma radioactivity, and of 4 min for the intact radiopharmaceutical, as identified with high-performance liquid chromatography. Urinary excretion accounted for >95% of the radioactivity within 24 h post injection, and up to 0.05% was found in the faeces up to 60 h. In all patients uptake of radioactivity was found in the areolae mammae (in women), liver, spleen, kidneys and urinary bladder. In eight patients a high uptake of [111In-DTPA-Arg1]-substance P was observed in the thymus. We conclude that, despite its short half-life, [111In-DTPA-Arg1]-substance P, a new radiopharmaceutical, can be used to visualize the thymus. This may contribute to the investigation of the role of thymus in immune-mediated diseases. In addition, inflammatory sites in various diseases could be visualized.

Extensive extramedullary hematopoiesis in a thyroid nodule

We describe a case of extramedullary hematopoiesis in a hyperplastic thyroid nodule from a patient with primary myelofibrosis. The presence of extensive extramedullary hematopoiesis in the thyroid gland was suspected as a result of fine-needle aspiration cytologic examination and was confirmed by histo- and immunomorphologic examination of the resected nodule. The diagnosis of myelofibrosis was established on the basis of clinical findings, hematologic laboratory results, and bone marrow morphologic characteristics.

Growth vs. DNA strand breaks in Hodgkin's disease: impaired proliferative ability of Hodgkin and Reed-Sternberg cells

We re-appraised the cell renewal pattern in Hodgkin's disease (HD), considering that most, though not all, Hodgkin/Reed-Sternberg (H-RS) cells exhibit abortive mitoses and that a substantial fraction of these exhibits DNA damage suggestive of imminent or actual cell death. Using combined immunohistochemistry and in situ end-labeling to detect strand breaks, the percentage per case of CD30+ (mainly H-RS) cells with DNA fragmentation (DNA fragmentation index [DFI]) was estimated. For each case, we registered the mitotic index (MI) of CD30+ cells and the percentage of Ki-67+ atypical large cells. To quantify the sum of our parameters for mitosis, whether successful or not, and DNA damage, we introduced the kinetic event index (KEI = MI + DFI). Only DFI and KEI distinguished significantly between mixed cellularity and nodular sclerosis HD. The values for MI and DFI, and therefore for KEI, CD30+ and CD30- small lymphoid cells were proportional. The percentages of Ki-67+ large atypical cells (median 50%) did not correlate significantly with either MIs or DFIs of CD30+ cells. Cluster analysis revealed the existence, independent of histological subtype, of 2 large groups of HD with different KEIs. Our findings suggest that cell deletion plays an important role in HD. Further, it appears that proliferation-associated antigens in H-RS cells do not reflect successful cell production in this disorder.

Expression of somatostatin receptors in normal, inflamed, and neoplastic human gastrointestinal tissues

The multiple actions of somatostatin are mediated by specific membrane-bound receptors present in all somatostatin target tissues, such as brain, pituitary, pancreas, gastrointestinal tract, and kidney. For instance, in the human gastrointestinal tract, three different types of tissue compartments express somatostatin receptors: the gastrointestinal mucosa, the peripheral nervous system, and the gut-associated lymphoid tissue, where the receptors are preferentially located in germinal centers. In all these cases, somatostatin binding is of high affinity and specific for bioactive somatostatin analogues. Somatostatin receptors are also expressed in pathological states, such as cancers. A particular abundance is found in neuroendocrine tumors of the gastrointestinal tract. Ninety percent of the carcinoids and a majority of islet cell carcinomas, including their metastases, usually have a high density of somatostatin receptors. Several different somatostatin-receptor subtypes can be expressed by these tumors, the SSTR2 subtype being the most frequently and abundantly expressed. The somatostatin receptors in tumors are identified with in vitro-binding methods, molecular biology techniques, or in vivo-imaging techniques; the latter allow the precise localization of the tumors and their metastases in the patients. Because somatostatin receptors in human gastroenteropancreatic tumors are functional, their identification can be used to predict the therapeutical efficacy of octreotide to inhibit excessive hormone release. Of differential diagnostic importance is the fact that other pathological processes in the gastrointestinal tract may be associated with a high density of somatostatin receptors. Ninety percent of lymphomas, including those with intestinal involvement express somatostatin receptors. Furthermore, a moderate number of colorectal carcinomas contain somatostatin receptors, whereas exocrine pancreatic carcinomas do not. Finally, an increased expression of SS receptors in nonneoplastic conditions, such as in intestinal veins in inflammatory bowel disease, has been recently observed. These observations demonstrate the ability of the human body to regulate SS receptors in a wide number of tissues and conditions.

Localized expression of mRNA for phagocyte-specific chemotactic cytokines in human periodontal infections

In bacterial infections, mononuclear and polymorphonuclear phagocytes are key components of host defenses. Recent investigations have indicated that chemokines are able to recruit and activate phagocytes. In particular, interleukin-8 (IL-8) attracts polymorphonuclear leukocytes (PMNs), while monocyte chemoattractant protein-1 (MCP-1) is selective for cells of the monocyte/macrophage lineage. In this investigation, we analyzed the in situ expression of IL-8 and MCP-1 mRNAs in human periodontal infections. Specific mRNA was detected by in situ hybridization using 35S-labeled riboprobes in frozen tissue sections. Phagocytes (PMNs and macrophages) were specifically detected as elastase-positive or CD68+ cells by a three-stage immunoperoxidase technique. Results indicated that expression of phagocyte-specific cytokines was confined to selected tissue locations and, in general, paralleled phagocyte infiltration. In particular, IL-8 expression was maximal in the junctional epithelium adjacent to the infecting microorganisms; PMN infiltration was more prominent in the same area. MCP-1 was expressed in the chronic inflammatory infiltrate and along the basal layer of the oral epithelium. Cells of the monocyte/macrophage lineage were demonstrated to be present in the same areas. The observed expression pattern may be the most economic way to establish a cell-type-selective chemotactic gradient within the tissue that is able to effectively direct polymorphonuclear phagocyte migration toward the infecting microorganisms and modulate mononuclear phagocyte infiltration in the surrounding tissues. This process may optimize host defenses and contribute to containing leukocyte infiltration to the infected and inflamed area, thus limiting tissue damage.

High density of somatostatin receptors in veins surrounding human cancer tissue: role in tumor-host interaction?

Somatostatin receptors were detected in peritumoral veins of various human cancer tissue specimens. Vascular and neoplastic tissue from 14 colonic adenocarcinomas, 13 carcinoids, 6 renal-cell carcinomas and 7 malignant lymphomas were analyzed for somatostatin receptors by use of quantitative receptor autoradiography. In colonic carcinoma specimens, the peritumoral vessels expressed a high density of somatostatin receptors, whereas the neoplastic tissue itself was receptor-negative in many cases. In contrast, the incidence and density of somatostatin receptors in peritumoral vessels was low in well-differentiated gastrointestinal and bronchial carcinoids, in contrast to the high density of such receptors in the carcinoid tumor tissue. Autochthonous vessels surrounding other tumors such as renal-cell carcinomas or malignant lymphomas also frequently expressed somatostatin receptors. In all cases, the somatostatin receptors were localized in veins, particularly in the smooth-muscle cell layer. They exhibited specific and high-affinity binding of somatostatin-14, somatostatin-28 and octreotide, suggesting a preferential expression of the SSTR2 receptor subtype. Since the vessels of normal non-neoplastic human tissues, e.g. of intestine or lymphatic organs, have few somatostatin receptors, the increased somatostatin receptor expression in peritumoral vessels observed in this study may be linked to the neoplastic process itself. The results suggest that somatostatin and somatostatin receptors may play a regulatory role for hemodynamic tumor-host interactions, possibly involving tumor stroma generation, tumor environment, angiogenesis and, particularly, vascular drainage of poorly differentiated neoplasms.

Epstein-Barr virus subtype distribution in angioimmunoblastic lymphadenopathy

The tissues of 16 patients bearing a T-cell lymphoma of angioimmunoblastic lymphadenopathy type (AILD-TCL) were investigated for the distribution of Epstein-Barr virus (EBV) subtypes 1 and 2. EBV-association had been proven in these cases by polymerase chain reaction (PCR) for EBV-DNA, in situ hybridization (ISH) for EBV-encoded small nuclear RNAs (EBER) and immunohistology for EBV-encoded latent membrane protein (LMP). PCR and EBER-ISH produced mostly identical results, but some cases were positive with only one of the 2 methods employed. LMP was detected in a few large cells of 8/13 cases. Twelve cases were investigated for the distribution of EBV subtypes. One case contained EBV genome of subtype 2, 3 cases contained subtype 1 and 4 cases contained both subtypes. Four cases could not be typed. These findings suggest that in AILD, as in AIDS-associated lymphomas and lymphomas of the lethal midline granuloma type, subtype 2 of EBV may occur, perhaps in relation to an immunodysfunction developing progressively in these patients.

Association of the subtype 2 of the Epstein-Barr virus with T-cell non-Hodgkin's lymphoma of the midline granuloma type

Lethal midline granuloma (LMG) is associated with Epstein-Barr virus (EBV). The latter has at least two subtypes with different biological properties. The subtypes can be identified by their genomic configuration. Using EBV-RNA (EBER) in situ hybridization and EBV polymerase chain reaction (PCR), we have looked for the presence of EBV in six LMGs and six non-Hodgkin's lymphomas (NHLs) located in the nasopharyngeal region, and determined the subtype of EBV. Six of six LMGs were positive by PCR and EBER in situ hybridization, whereas NHLs were either negative or, in three of six cases, showed few EBER-positive cells considered to be nonneoplastic lymphocytes. The subtype 2 was found in LMG lesions of three of six patients; the remaining three of six patients with LMG had the generally occurring subtype 1. The results indicate that the association of EBV with NHL may depend more on tumor type than on its localization. The occurrence of the rare subtype 2 in LMG may relate to a covert immune defect.

Preferential location of somatostatin receptors in germinal centers of human gut lymphoid tissue

Somatostatin receptors were evaluated in four human gut-associated lymphoid tissues (palatine tonsils, ileal Peyer patches, vermiform appendix, and colonic solitary lymphatic follicles) using receptor autoradiography on tissue sections incubated with 125I[Tyr3]octreotide. All four tissues were somatostatin-receptor positive; the receptors were preferentially located in the germinal centers, with the luminal part of the center more strongly labeled than the basal part. The corona of the follicles and the primary follicles without germinal centers did not display somatostatin receptors. The receptors were of high affinity (Kd = 1.3 +/- 0.6 nmol/L) and specific for somatostatin. Displacement by nanomolar concentrations of somatostatin 14, somatostatin 28, and octreotide was observed, as was guanosine triphosphate dependency. The gastrointestinal mucosa and the plexus submucosus and myentericus also contained somatostatin receptors. These data strongly suggest that the germinal centers of the gut-associated lymphoid tissue are a site of action of somatostatin. It possibly mediates antiproliferative effects and inhibits immunoglobulin synthesis in the activated lymphoid cells. The human gut represents a multifaceted target for somatostatin action, in which at least three different tissues (mucosa, nerve plexus, and lymphoid tissue) are involved.

Somatostatin receptors in human cancer: incidence, characteristics, functional correlates and clinical implications

Somatostatin receptors (SS-R) have been identified in membrane homogenates or tissue sections from several hundred tumors. SS-R were found in most neuroendocrine tumors, i.e. GH and TSH producing pituitary tumors, endocrine gastroenteropancreatic (GEP) tumors, paragangliomas, pheochromocytomas, medullary thyroid carcinomas (MTC) and small cell lung carcinomas. SS-R were also expressed in a majority of malignant lymphomas, in several brain tumors (all meningiomas, most astrocytomas) and in breast tumors. The majority of tumors expressing SS-R are rather differentiated (i.e. astrocytomas vs glioblastomas), but exceptions exist (high grade malignant lymphomas). An inverse relationship exists between SS-R and receptors for epidermal growth factor (EGF-R) incidence in lung tumors, glial tumors and most breast tumors, whereas meningiomas express simultaneously both receptors. A minority of tumors (ovarian tumors, MTC, insulinomas) express a subtype of SS-R, characterized by low affinity for the octapeptide SS analog octreotide. The function mediated by SS-R in human tumors may differ according to the tumor type. SS-R in pituitary and GEP tumor mediate hormone secretion inhibition with, in addition, possibly some antiproliferative effects. In meningiomas, however, activation of SS-R inhibits forskolin-stimulated adenylate cyclase activity, and weakly stimulates proliferation. Whereas SS-R seem to mediate antiproliferative effects in animal models and cell lines of lymphomas, breast and lung tumors, such an effect has not yet been convincingly documented in human primary tumors. The clinical implications of the presence of SS-R in tumors are manyfold: (1) as a predictive marker for efficient therapy with octreotide in pituitary and GEP tumors; (2) as a diagnostic marker: for pathobiochemical classification of tumors, using in vitro detection methods; for clinical evaluation using in vivo scanning techniques; (3) as a prognostic marker; and (4) as a potential radiotherapeutic target.

Enteropathy-associated T-cell lymphoma in a renal transplant patient with evidence of Epstein-Barr virus involvement

The clinical and histological findings in a 54-year-old patient with enteropathy-associated T-cell lymphoma (EATL) occurring 18 years after renal transplantation are presented. Ten years after adult-onset coeliac disease the patient developed medium to large T-cell non-Hodgkin's lymphoma of the small intestine. Epstein-Barr virus (EBV) genome was detected by polymerase chain reaction in the lymphoma tissue and localized via Epstein-Barr virus RNAs in situ hybridization to some of the tumour cells. This is the first case report of EBV-positive EATL occurring in the setting of immunosuppression.

Immunohistochemical characterization of the human endolymphatic sac and its associated cell populations

The use of monoclonal and polyclonal antibodies as specific markers for the localization of tissue constituents in situ allows the characterization of cells according to their state of differentiation and the detection of cellular antigens related to the function of cells and tissues. Our studies focus on the immunohistochemical characterization of the human endolymphatic sac (ES) and its associated cell populations. A panel of 37 monoclonal and polyclonal antibodies were used on frozen sections and fixed material from 64 ES of 32 persons without any clinically known inner ear disorders. The ES were removed at the time of autopsy; case histories were available. The results of our studies on the extraosseous part of the human ES support the assumption that the epithelium is metabolically active and capable of both secretion and absorption. The reactivity of the epithelial cells with antibodies against neuron specific enolase, chromogranin and somatostatin, respectively, implies a paracrine activity of the ES. Further results obtained with antibodies specific for cells of the immune system indicate a possible role of the human ES in the inner ear immune defence and a functional relationship of the ES to the common mucosa-associated immune system.

Functional morphology of the human endolymphatic sac. A review

Modern immunohistochemical methods allow a functional characterization of the human endolymphatic sac (ES) and its associated cell populations. The currently available immunohistochemical data on the extraosseous part of the human ES support the assumption that the epithelium is metabolically active and capable of both secretion and absorption. The reactivity of some epithelial cells with antibodies against neuroendocrine antigens implies a paracrine activity of the human ES. Further results provide evidence for a possible role of the human ES in inner ear immune defense and indicate a putative functional relationship of the human ES to the common mucosa-associated immune system.

Somatostatin receptor incidence and distribution in breast cancer using receptor autoradiography: relationship to EGF receptors

Somatostatin receptors (SS-R) were measured with in vitro receptor autoradiography using the SS analog 125I-[Tyr3]-SMS 201-995 as radioligand in 342 breast-tumor samples. In a group of 158 "small" tumor samples (mean section surface: 14 mm2 +/- 0.4; mean +/- SEM), 34 tumors (21%) were SS-R positive. In a group of 72 "large" tumor samples (mean size: 180 mm2 +/- 8; mean +/- SEM), 33 tumors (46%) were SS-R positive. In this second group, more than half of the tumors had a non-homogeneous distribution of SS-R, i.e., tumor regions within SS-R positive tumors were SS-R negative. In a group of 48 additional patients, we could show that primaries and their metastases, or double primaries from right and left breasts, or 2 primaries resected consecutively, could both occasionally be SS-R positive. Finally, in 71 SS-R-positive primary tumors, 18 tumor samples were found to have simultaneously Epidermal Growth Factor receptors (EGF-R); in 12 of these 18 cases, the 2 receptor types were not topographically overlapping. Whereas SS-R were located on tumor tissue, EGF-R were often seen on adjacent normal lobules and ducts. These results show that a subgroup of breast tumors contain SS-R, in several cases non-homogeneously distributed. Their location does not coincide with that of EGF-R. Metastasis of SS-R-positive primaries may be SS-R-positive, as are sometimes second primaries. For evaluation of SS-R incidence and distribution, autoradiography is of advantage, specially if it is performed on large tumor samples, since it allows precise identification of the tissue elements containing these receptors.

Germinal center kinetics in lymph nodes of primed mice stimulated with complexed as opposed to free antigen

Primed mice with low titers of circulating tetanus antitoxin (AB) were stimulated via the hind footpads with either fluid tetanus toxoid alone (AG) to create in vivo complexes in AG excess, or the same dose of toxoid complexed at equivalence with isologous antibody (AB-AG CPX), to have in vivo complexes in AB excess. All experimental animals reacted with three topically distinct consecutive waves of enhanced proliferative activity in popliteal lymph nodes, i.e., in the T-zone (peak on day 2), in the medullary area, the main site of plasmocytopoiesis (day 3), and in lymphoid follicles (day 5-6). Maximum serum AB titers following injection of AG-AB CPX were only about 25% of those found in animals boosted with AG alone. This suppressive effect was best reflected in a comparable reduction in plasmocytopoiesis, and to an lesser extent in the proliferative activity within the T-zone, and not at all in the overall magnitude of germinal center formation and/or expansion. However, the patterns of germinal center kinetics differed markedly between the two groups: a high sharp peak of development on day 5, followed by a marked drop on day 6 characterized the response in mice given AG alone, and a broad peak around day 6 that of those receiving AG-AB CPX. These differences could not adequately be accounted for by variations in centroblast/centrocyte proliferation rate vs. pycnotic indices, so that different patterns of lymphoid cell emigration from the centers may be considered. The results suggest that immune complexes, fixed on follicular dendritic cells, with different antigen-to-antibody ratios have divergent effects on the development and kinetics of germinal centers, the principal sites of memory B cell generation.

[Renal manifestations of sarcoidosis]

Renal manifestations of sarcoidosis are rare. In addition to calcium nephropathy, granulomatous interstitial nephritis and glomerulo-nephritis (GN) account for most cases. The latter two manifestations are described in 4 patients and in a detailed review of the literature. In comparison to a nonselected population of sarcoidosis patients, granulomatous interstitial nephritis is found more frequently in male patients above 40 years of age; it is associated more frequently with other extrathoracic manifestations of sarcoidosis; and it causes renal insufficiency of varying degree, which is at least partially reversible with steroid therapy. Predominant findings are silent microhematuria, sterile pyuria, mild proteinuria and a variety of tubular functional disorders. Glomerulonephritis (39 observations) has been described with increasing frequency in sarcoidosis. Because of the well known immunological abnormalities of sarcoidosis, frequent association of sarcoidosis with GN could be expected but this association has not yet been proven statistically. Sarcoidosis-associated GN includes a variety of histological forms, viz. membranous, proliferative and sclerosing GN. Glomerulonephritis may appear before sarcoidosis. Conversely, both diseases may appear simultaneously, or GN may follow all other manifestations of sarcoidosis with a latency period of many years.

[Acquired cystic renal changes--a clinically relevant problem in long-term dialysis]

While dialysis patients survive renal failure for years and even decades, multiple morphologic alterations take place in their kidneys. One of these (so to speak) "postmortem" changes is the formation of secondary renal cysts. A patient with end stage renal failure due to amyloidosis is described who was dialysed at home for 9 years. Intravenous pyelography and renal biopsy in the predialysis period likewise documented the presence of amyloidosis and the absence of cystic disease. Ultrasonography of both kidneys, a suspicious increase in hematocrit and the autopsy finding of numerous large cysts also showed the presence of acquired cystic disease. The frequency and complications of this newly recognized disease in longterm dialysed patients are discussed. Recommendations are given concerning follow-up of these patients, with a view to early detection of tumor development within the cysts.

Somatostatin (somatostatinlike) immunoreactive cells in the human inner ear

Certain epithelia of the human inner ear and human endolymphatic sac display somatostatin and/or somatostatin-like immunoreactivity. Histologic sections from 13 human temporal bones and from 15 endolymphatic sacs were studied using the unlabeled antibody peroxidase-antiperoxidase technique. The somatostatin and/or somatostatin-like immunoreactive cells were located exclusively in the covering epithelium of the spiral prominence and in the epithelium of the intermediate and rugosal part of the endolymphatic sac. In the epithelium of the spiral prominence and endolymphatic sac, secretory granules of the same size and appearance as those of intestinal or pancreatic somatostatin-producing cells were demonstrated ultrastructurally. The findings are consistent with a local exocrine, paracrine, and/or endocrine system of the inner ear.

Secretory immunoglobulin A in the human endolymphatic sac. An immunohistochemical study

Presence of immunoglobulin A (IgA) and of secretory component in epithelial cells and in the lumen of the human endolymphatic sac was demonstrated by two different immunohistochemical methods. IgA was also detected in perisaccular plasma cells. The findings connote the existence of a local immune system of the inner ear.

[Chronic defibrination syndrome and thrombocytopenia in splenic hamartoma (splenoma)]

In a 41-year-old woman who had suffered from hypofibrinogenemia, thrombocytopenia, leukopenia and splenomegaly for several years a causative hamartoma of the spleen (splenoma) was removed surgically. The results of a preoperative therapeutic trial with heparin, the marked accumulation of 125I-activity in the splenoma following intravenous injection of radioiodinated fibrinogen, the immunohistochemical demonstration of extensive fibrinogen deposits in the splenoma, and normalization of fibrinogen levels and blood cell counts after surgery point to the pathogenetic role of this rare splenic tumor. The salient clinical and pathological features of 41 splenoma cases in the literature are briefly reviewed. Hematologic signs were observed in only 9 splenoma patients.

[Hemangio-endothelioma of the liver (case report) (author's transl)]

The infantile hemangio-endothelioma (IHE) of the liver, a rare neoplasm, may lead the clinician and the surgeon to suspect the presence of a malignant tumor, whereas histologic examination often reveals a benign condition; our case report illustrates this discrepancy in a 3 1/2-month-old girl suffering from multiple nodules in the liver. Conservative steroid treatment resulted in a marked reduction in tumor size; the girl is in good health more than two years after diagnosis. More than 80% of hepatic IHE are diagnosed during the first six months of life. Hepatomegaly, congestive heart failure and hemangiomas of the skin combine to the classic symptomatic triad. Since the mortality is high in untreated cases, early diagnosis is of importance. IHE may regress spontaneously. Therefore, conservative therapy, such as steroid medication and treatment of the secondary, tumor-induced complications appear indicated. Alternatively, embolization and/or resection of the tumor may be considered. Signs of cardiac or hepatic insufficiency at diagnosis and a low degree of histologic differentiation are of unfavorable prognostic significance.

[Megalocytic interstitial nephritis. A contribution to the differential diagnosis of the large insufficient kidney]

After a female patient had presented with advanced renal failure, bilateral enormous increase in kidney size radiologically, urinary tract infection (E. coli) and septicemia, autopsy disclosed megalocytic interstitial nephritis (MIN). Clinical and pathological differentiation from renal parenchymal malakoplakia (RPM) is discussed. A literature survey of 15 cases of MIN and 35 observations of RPM points to certain differences between the two entities, i.e. an increased incidence of bilateral pathology in MIN, mor frequent extrarenal localizations in RPM, absent Michaelis-Gutmann bodies and a predominantly cortical distribution in MIN. The similarities, however, suggest that the two conditions might represent different stages of one and the same disease process.

[Intravascular uterine leiomyomatosis]

Intravascular (intravenous) leiomyomatosis is a rare uterine neoplasm. The unusual growth and extension of histologically benign smooth muscle tumors in vascular channels of uterus and pelvis are cardinal features of the disease. The course of the affection has been benign in the majority of the cases reported in the literature. Clinical and pathologic aspects are briefly evaluated in the context of an example of intravascular leiomyomatosis in a 30-year-old woman.

Kinetic studies on glial, Schwann and capsular cells labelled with [3H] thymidine in cerebrospinal tissue of young mice

Neuroglia, capsular and Schwann cell renewal and turnover in the cerebellum, the spinal cord and spinal ganglia have been evaluated in 2-months-old mice. The animals received intraperitoneal injections of [3H] thymidine at 8 hr intervals starting on the 28th day of postnatal life for a period of 30 days and were killed 1 hr after the last injection. Substantial numbers of labelled neuroglial cells but no labelled neurons were observed. Oligodendrocytes of the cerebellum and the spinal cord showed higher labelling indices (19.8% and 18.0%, respectively) than astrocytes (10.0%) and Bergmann's supporting cells (7.2%). The labelling indices of capsular cells in the spinal ganglia and Schwann cells in the spinal roots were 35.8% and 25.8%, respectively. The experiments failed to provide evidence for matrix cell layers in the cerebellum, the spinal cord and spinal ganglia. It may be concluded therefore that glial and Schwann cells in these parts of the nervous system proliferate in situ.

Survival of chromium-51-labeled autologous and homologous erythrocytes in goats

Apparent half-survival time of 51-Cr-tagged caprine erythrocytes after autotransfusion was 8 days. The 51Cr-tagged homologous caprine erythrocytes disappeared from circulation very rapidly, thereby indicating that it is not possible to produce sustained polycythemia in goats by hypertransfusing them with homologous erythrocytes without appropriate matching.

Selective damage to erythroblasts by 55-Fe

The low energy and short range of 55-Fe Auger electrons were utilized in mice to deliver lethal intracellular radiation to iron-incorporating erythropoietic precursors with minimal radiation damage to other bone marrow cells. The ensuing intramedullary, selective erythropoietic death was demonstrated by absolute and differential bone marrow cell counts and by decreased blood uptake of 59-Fe. The decreased number of colony-forming units in spleen colony assay and the decreased ability of tranplanted bone marrow to protect fatally irradiated mice shows that the bone marrow was partially depleted of pluripotent stem cells. These data are interpreted to indicate an increased pluripotent stem cell utilization in response to increased demand for differentiation of stem cells along the erythropoietic pathway.